Most HVAC systems used for providing temperature control of architectural spaces include a thermostatic controller, such as a thermostat, that is mounted on the wall of the space, for controlling the temperature of the space. Such thermostatic controllers typically include an internal temperature sensitive element for sensing the present room temperature of the space, an input element for receiving an input designating a desired room temperature, and a dial or digital display that can be viewed by a person operating the controller. Alternatively, such controllers are sometimes adapted to receive a present room temperature and/or a desired temperature signal from a sensor or input element located in the space at a point remote from the controller. A typical controller may also include output elements such as relays, switches, or electronic drive circuits for sending a control signal to the HVAC system.
Sometimes the dial or digital display of the thermostatic controller is illuminated, or can be lighted by pressing a button on the controller, so that the dial or display can be seen more clearly. Although such an illumination feature facilitates operation of the thermostatic controller, it is still typically necessary to be standing in very close proximity to the controller in order to read the dial or display to view the information displayed thereon. It is desirable to have a method and apparatus for visually indicating the present room temperature and in a manner that does not require a person to be standing in close proximity to the controller. This is particularly true for persons who have difficulty in walking, or who have impaired vision.
Prior approaches to providing a visual indication of the present room temperature, on the dial or display of a thermostatic controller, have also not been aesthetically pleasing. Permanently illuminated dials or displays are distracting, and are generally totally utilitarian in nature. Having a lighted display indicating the present temperature in numerals that are big enough to be viewed from a point even a foot or two away from the controller is generally neither practical nor aesthetically pleasing.
It is desirable, therefore, to have an improved method and apparatus for providing a visual indication of present room temperature on a thermostatic controller, in a manner that can be viewed at some distance from the controller, and in a manner that is aesthetically pleasing.